Such a filter apparatus is known (WO 94/17981). Within this known apparatus, each one of the scraping edges is constituted by a plurality of scraper elements separated from each other and pressed against the filter either by means of springs or by means of the pressure of the supplied liquid to be filtered. In the latter case, the scraper elements are movably connected to the scraper carrier by means of pins directed perpendicular to the filter surface so that each element can move along the pins, and each scraper element is so designed that the pressure exerted on it by the supplied liquid in direction towards the filter is greater than the pressure acting in the opposite direction. Both embodiments, however, suffer from the disadvantage that a solid particle can adhere between the filter and the scraper element, so that it is not engaged by the scraping edge of the scraper element. Then, this solid particle keeps the scraper element spaced apart from the filter surface to be cleaned so that the respective scraper element becomes inactive. This leads not only to a decrease of the cleaning effect on the upstream-side filter surface, but frequently causes also an additional wear on this surface by solid particles conveyed always along a circle and having frequently sharp edges.